Seasonal affective disorder (SAD), also known as winter depression, is a problem all too familiar to New Englanders and others who live in northern latitudes. SAD is “not just feeling bummed out because it’s winter,” said Janis Anderson, director of the seasonal affective disorder service at Brigham and Women’s Hospital. It includes physical changes such as trouble getting up in the morning, lack of energy, gaining weight and problems concentrating, for weeks or months at a time. Symptoms typically start in the fall and lift in the spring.
SAD is actually a bad name for this common disorder, which to a mild or moderate degree affects 25 percent of people living at latitudes like New England’s and strikes 5 percent so badly they meet the criteria for major depression. A better name would be “light deprivation disorder,” said Dr. Dan Oren, a SAD specialist and psychiatrist at Yale University and the Veterans Affairs Medical Center in W. Haven, CT.
Given that SAD appears to be triggered by lack of sunlight, it’s not surprisingly that the most effective treatment is to restore this bright light, either by getting outside even in winter or by sitting in front of a light box for 30 to 90 minutes a day, preferably in the morning.
No one knows biochemically how exposure to light affects behavior and mood, though most animal species are sensitive to light’s effects. But a number of studies shows that light therapy does work for SAD, as do antidepressants like Prozac.
But consumer beware: Not all light boxes sold on the Internet are safe and effective because some wave lengths, especially those used for tanning, can damage eyes, said Anderson. For information on SAD and light boxes, visit www.sunboxco.com, www.cet.org/cet2000 (the Center for Environmental Therapeutics) or www.sltbr.org (the Society for Light Treatment and Biological Rhythms.) Be sure to get a light box with fluorescent bulbs that provide 10,000 lux (a measure of intensity). (That’s a lot more than ordinary room light.) The boxes can cost around $400, but most insurers now pay.